Cam wedge power clamp



May 7, 1968 L.. F. BLATT 3,381,954

CAM WEDGE POWER CLAMP Filed Oct. 20, 1965 3 Sheets-Sheet. l

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CAM WEDGE POWER CLAMP Filed Oct. 20, 1965 5 Sheets-Sheet 2 FIC-3.3

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ATTORNEYS May 7, 1968 1 F. BLATT CAM WEDGE PGWER CLAMP 5 Sheets-Sheet 3 Filed Oct. 20, 1965 INVENTOR LELAND F. BLATT Y (3%., lm (M ATTORNEYS United States Patent O 3,381,954 CAM WEDGE POWER CLAMP Leland F. Blatt, Grosse Pointe, Mich. (24121 Mound Road, Warren, Mich. 48091) VFiled Oct. 20, 1965, Ser. No. 498,478 2 Claims. (Cl. 269-32) ABSTRACT F THE DISCLOSURE A pivotally mounted clamping arm is actuated by a cylinder operated clevis which is provided with a roller riding in an eccentrically oriented slot in the clamping arm. J-shaped cover plates coplanar with the legs of the clevis and pivotally mounted for pivotal movement with the clamping arm` shield the clamping arm slot from debris which might otherwise jam the mechanism.

This invention relates to cylinder operated power clamps, and more particularly to improved actuating linkages for such clamps.

Power clamps are frequently used to secure a workpiece to a machine or fixture while an operation such as cutting or welding is being performed on the workpiece. Such operations frequently produce debris in the form of cuttings or weld fiash, which tends to get into the clamp linkage and jam the mechanism. These mechanisms generally include oscillating elements, which are difficult to shield from such debris, since any stationary housing or shield must be spaced from these elements to permit free travel of the mechanism. Debris may thus enter through these spaces. Y

Accordingly, it is an object of this invention to provide a cylinder operated power clamp having its actuating mechanism shielded from debris produced by associated operations.

Other objects, advantages and novel features of this invention will become apparent from the following specification, when considered in conjunction with the accompanying drawings.

In these drawings:

FIG. 1 is a plan view of the power clamp of this invention;

FIG. 2 is a front elevation of the clamp of FIG. 1;

FIG. 3 is an end view section taken along line 3-3 of FIG. 2;

FIG. 4 is a fragmented section taken along line 4-4 of FIG. l, with the guide arm shown in phantom;

FIG. 5 is a section similar to FIG. 4, but showing the mechanism at the other end of its stroke;

FIG. 6 is an exploded perspective Vview of the guide body and linkage portion of the power clamp.

Referring now to FIGS. 1, 2, and 6, a cylinder operated power clamp 10 is supported in a mounting bracket 12. Power clamp 10 generally consists of an actuating cylinder 14, a bifurcated guide body 16 including a pair of spaced legs 17, and a clamping arm 18 which is pivotally mounted to guide body 16 by pivot bolt 20. Clamping arm 18 is illustrated without any particular fixtures secured to its end, it being understood that the particular application of the power clamp does not form a part of this invention.

Within the actuating cylinder 14 a piston (not illustrated) is actuated by means of either pneumatic or hydraulic pressure admitted to the cylinder through ports 21. The reciprocating motion of the power piston is transferred to clevis 22 by a rod 24, which is secured to both the power piston and clevis 22.

A pair of rollers 26 is mounted on a shaft 28 which passes through the two arms of clevis 22. Rollers 26 ride in guide slots 30 formed in the inner opposed faces of 3,381,954 Patented May 7, 1968 ICC the two legs 17 of the guide body 16 (see FIGS. 1, 3, and 6). Mounted on the center portion of shaft 28 is a roller cam 32, which is inserted in an inclined slot 34 in clamping arm 18.

A pair of I-shaped cover plates 36 is pivotally mounted on bolt 20. Cover plates 36 overlap the lower portion (as viewed in FIGS. 2 and 6) of clamping arms 18, each platebeing coplaner with and directly below one of the arms of clevis 22. These plates follow the contour of the lower portion of slot 34, and a hooked-shape portion 40 passes around the right hand end of slot 34. Hook portion 40 is contoured to correspond in shape with the end of`clevis 22. A pin 38 passes through cover plates 36 as well as arm 18, so that the cover plates are constrained to pivot in conjunction with guide arm 18.

It is contemplated that arm 18, clevis 22 and cover plates 36 be so dimensioned as to be in substantially face to face contact with each other as viewed in FIGS. 1 and 3. That is, arm 18 would be wide enough to substantially fill the gap between cover plates 36 and between the legs of clevis 22, and clevis 22 would substantially till the gap between the inner opposed faces of body legs 17. This face to face contact between these elements aids in shielding the mechanism from debris as will be more fully discussed hereinafter. For clarity of illustration, a slight gap is shown in the drawings between these parts.

Operation As the power piston and clevis make their stroke from right to left (that is, from the position shown in FIG. 4 to that shown in FIG. 5) the roller cam 32, being constrained by shaft 28 to follow the horizontal path of rollers 26 in guide slots 30, forces the slot 34 and arm 18 (both shown in -phantom in FIGS. 4 and 5) to rotate counter-clockwise about pivot bolt Ztl. Similarly, cover plates 36 follow the path of clamping arm 18.

When the mechanism is in the position shown in FIG. 4, slot 34 is shielded by the two arms of clevis 22 and by hook portions 40 of cover plates 36, which snugly abut and follows the contour of the right hand end of the clevis arm.

However, when the mechanism is in the position shown in FIG. 5, part of slot 34 would be exposed, without the provision of the eXtra shielding provided by the hook portion 40 of cover plates 36. That is, the upper end of slot 34 lies above the otherwise enclosing and overlapping legs of clevis 22 (see FIG. 5) and there is thus an unprotected gap between slot 34 and the inner faces of legs 17 of guide body 16. It can be seen from FIG. 5 that the hook-shaped portion 40 of the clamping arm lies above slot 34 and very nearly abuts the upper surface of clevis 22. Cover plates 36 are therefore in a position to block any foreign matter which might otherwise drop into the mechanism from the cutting or welding operation being performed. Additional protection is provided by the fact that roller slot 34 lies completely within body 16 in all positions of arm 18. That is, as viewed in FIG. 5, slot 34 never projects above or below the outline of guide body 16 The invention may be further developed within the scope of the following claims. It is to be understood, therefore, that the above description is illustrative of only a single embodiment of the invention, and is not to be read in a strictly limited sense.

I now claim:

1. In a cylinder operated power clamp system characterized by a power cylinder, a piston reciprocable in said cylinder, actuating means `for reciprocating said cylinder and mounting means for securing the clamping system to a support, the improved clamp actuating linkage which comprises:

a guide body, having a pair of spaced apart legs, se-

cured to said mounting means and axially aligned with the power cylinder, the inner opposed faces of the legs of said body being provided with longitudinal guide slots;

a clamping arm pivotally mounted between the legs of said guide body for oscillating movement in a plane parallel to said legs, the pivotal mounting axis of said clamping arm being transverse to the axes of said guide slots and non-intersecting;

said clamping arm being so dimensioned as to be smaller in thickness than the space between the legs of said guide body;

said clamping arm having a follower slot formed therea U-shaped clevis secured to the power piston for reciprocating movement therewith and disposed within the space between said guide body legs, said clevis having guide rollers mounted thereon disposed in said guide slots;

a roller cam mounted on said clevis and disposed within said clamping arm follower slot, whereby reciprocation of said power piston produces oscillation of the clamping arm;

said clamping arm being sandwiched between a pair of J-shaped cover plates which substantially ll the gap between said clamping arm and the inner opposed faces of said guide body legs;

said cover plates being fixed to said clamping arm for oscillation therewith, and the hook portion of the I passing around one end of said follower slot so as to shield the follower slot from falling debris when said clamping arm is pivoted to a substantially vertical position.

2. In a power clamp system comprising a fixed, U- shaped, horizontally disposed guide body having a forward end and a rearward end and a pair of spaced apart horizontal forwardly extending legs; a powered drive link in the form of a U-shaped clevis arranged between said 4 guide body legs; a clamping arm having an end portion litted between the legs of the clevis and extending forwardly of said guide body; a pivot pin transversely and horizontally extending between said guide body legs and through said arm end -portion and beneath said clevis, whereby said arm is pivotally mounted on said pivot pin for oscillating movement in a vertical plane between said guide body legs; the inner opposed faces of said guide legs having longitudinal, inwardly opening guide slots; said clamping arm having a slot extending through its end portion, said slot being inclined to the longitudinal axis of said arm; and a roller fitted into said inclined slot, said roller being arranged on a horizontally arranged pin which extends through the legs of said clevis and whose opposite ends are slidably mounted within the respective guide body guide slots; the improvement which comprises:

a pair of cover plates, each arranged on opposite sides of said clamping arm end portion between Said end portion and said guide body legs;

said cover plates being disposed beneath and in parallel alignment with a respective clevis leg and substantially filling the space between said arm end portion and said guide body legs;

said cover plates each being substantially I-shaped, with the hook portion of the J closely following the contour of the periphery of the forward end of said inclined slot for shielding the slot from falling debris when said arm is pivoted into a substantially vertical position.

References Cited UNITED STATES PATENTS 2,845,847 8/1958 Blatt 269-32 X ROBERT C. RIORDON, Primary Examiner.

I. F. MCKEOWN, Assistant Examiner. 

